As the case stands,
the self-fertilised plants of the successive generations in Table 7/A
were put into competition with and compared with intercrossed plants,
which were probably deteriorated in some degree by being more or less
inter-related and grown under similar conditions. Nevertheless, had I
always followed the plan in Table 7/C, I should not have discovered the
important fact that, although a cross between plants which are rather
closely related and which had been subjected to closely similar
conditions, gives during several generations some advantage to the
offspring, yet that after a time they may be intercrossed with no
advantage whatever to the offspring. Nor should I have learnt that the
self-fertilised plants of the later generations might be crossed with
intercrossed plants of the same stock with little or no advantage,
although they profited to an extraordinary degree by a cross with a
fresh stock.
With respect to the greater number of the plants in Table 7/A, nothing
special need here be said; full particulars may be found under the head
of each species by the aid of the Index. The figures in the right-hand
column show the mean height of the self-fertilised plants, that of the
crossed plants with which they competed being represented by 100. No
notice is here taken of the few cases in which crossed and
self-fertilised plants were grown in the open ground, so as not to
compete together.
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